Borrowed Trust: Parasocial Relationships, Authenticity Work, and Value Creation in Influencer Marketing — A Multiple-Case Analysis

Influencer marketing has grown from a fringe tactic into a channel valued at roughly US$32.5 billion in 2025, yet our understanding of why it works—and why it occasionally fails spectacularly—remains fragmented across single-variable experiments. This paper steps back from that variable-by-variable view to ask a processual question: through what mechanism does a paid recommendation from a comparatively ordinary, non-expert stranger move markets, and what separates campaigns that build durable value from those that destroy it? Using a theory-elaborating multiple-case design, we examine four documented campaigns selected for maximum variation in outcome, sector, influencer tier, and era—Daniel Wellington, Gymshark, the Fyre Festival, and Stanley's Quencher—reading them against source-credibility theory, parasocial-relationship theory, the persuasion-knowledge model, and recent work on authenticity. We argue that the central asset is not reach but borrowed trust: the parasocial credibility an audience has already extended to a creator, which a brand temporarily draws upon.

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